竞争包结法研究β-环糊精及其衍生物对灯盏花乙素的选择键合

以酚酞作为光谱探针,采用紫外-可见光谱滴定法测定了β-环糊精(β-CD),单(6-脱氧-乙二胺)-β-环糊精(en-β-CD),单(6-脱氧-二乙基三胺)-β-环糊精(dien-β-CD),羟丙基-β-环糊精(HP-β-CD),磺丁基醚-β-环糊精(SBE-β-CD)在30℃时,pH=10.50的0.025mol/L缓冲液中与灯盏花乙素所形成超分子配合物的稳定常数。结果表明,多种弱相互作用力协同作用于环糊精的配位过程,主-客体间的尺寸匹配决定所形成配合物的稳定性,环糊精衍生物的取代基影响主体的配位能力。5种环糊精主体化合物对灯盏花乙素客体分子的包合能力大小为:β-CDSBE-β-CDen-β-CDdien-β-CDHP-β-CD。     

水杨酸甲酯在β-环糊精水溶液中的双重荧光光谱

研究了β-环糊精(β-CD)及其衍生物甲基-β-环糊精(M-β-CD)、羟丙基-β-环糊精(HP-β-CD)对水杨酸甲酯(MS)双重荧光光谱的影响,并将其与MS在不同溶剂中的荧光光谱进行对比。结果表明,MS的双重荧光与所处微环境的氢键性质密切相关,β-CD取代基的大小会导致空腔口处的极性和空间位阻不同,相应改变了分子间氢键相互作用,当MS分子进入β-CDs空腔时会引起其基态互变异构体之间平衡的移动,从而导致光谱的变化。包合物稳定常数测定表明,三种β-CDs对MS包合能力的大小为M-β-CD>HP-β-CD>β-CD。     

β-环糊精衍生物对昔康类药物的增溶作用

相溶解度法研究了吡罗昔康、美洛昔康和氯诺昔康与β-环糊精(β-CD)、磺丁醚-β-环糊精(SBE-β-CD)和羟丙基β-环糊精(HP-βCD)的包合特性.结果表明,昔康类药物与3种环糊精都形成了1:1的包合物.环糊精包合能力HP-β-CD>SBE-β-CD>β-CD.增溶效应氯诺昔康>美洛昔康>吡罗昔康.     

LNG-HP-β-CD包合物制备、表征及其紫外稳定性研究

左炔诺孕酮(LNG)不溶于水和紫外光照易分解的特点,限制了其在鼠类不育剂中的应用.该研究采用溶液法,制备出LNG的羟丙基-β-环糊精(HP-β-CD)包合物,建立了准确简便的紫外光谱定量检测方法;通过相溶解度法确定了HP-β-CD与LNG的包合摩尔比为1:1,25℃时LNG-HP-β-CD包合物的稳定常数为187.3 ...     

LNG-HP-β-CD包合物制备、表征及其紫外稳定性研究

左炔诺孕酮(LNG)不溶于水和紫外光照易分解的特点,限制了其在鼠类不育剂中的应用。该研究采用溶液法,制备出LNG的羟丙基-β-环糊精(HP-β-CD)包合物,建立了准确简便的紫外光谱定量检测方法;通过相溶解度法确定了HP-β-CD与LNG的包合摩尔比为1∶1,25 ℃时LNG-HP-β-CD包合物的稳定常数为187.3 L·mol-1;通过紫外光谱、傅里叶变换红外光谱表征,验证了包合物的形成;对包合物的抗紫外光降解性能进行了测试,表明在50 h内包合物的降解率小于5%,远低于药物单体。结果表明,HP-β-CD对LNG具有良好的包合作用,可显著提高该药物的水溶性和紫外稳定性。     

RP-HPLC测定不同β-环糊精衍生物超分子包合物中褪黑激素的含量

建立了反相高效液相色谱法测定褪黑激素(MLT)与羟丙基-β-环糊精(HP-β-CD)、甲基-β-环糊精(M-β-CD)以及取代度为1、4、7的3种磺丁基醚-β-环糊精(SBE1-β-CD、SBE4-β-CD、SBE7-β-CD)共5种不同β-环糊精衍生物所形成的超分子包合物中褪黑激素含量的分析方法。采用Agilent Extend C18色谱柱(4.6mm×150mm,5μm),流动相为甲醇-水(40∶60),流速0.8mL/min,柱温:室温,检测波长278nm。结果表明:褪黑激素在5.05—202μg/mL浓度范围内线性关系良好(r=1.000);平均加标回收率分别为99.8%、99.0%、100.4%、99.9%、100.6%;RSD分别为0.53%、1.0%、0.71%、0.94%、0.86%。本方法可用于各类褪黑激素超分子包合物的含量分析。     

荧光光谱法研究山奈素与β-环糊精及其衍生物包合作用

采用荧光光谱法研究了β-环糊精(β-CD)、甲基-β-环糊精(M-β-CD)、羟丙基-β-环糊精(HP-β-CD)、磺丁基-β-环糊精(SBE-β-CD)与山奈素的包合特性.在固定山奈素浓度和改变环糊精及其衍生物浓度的情况下,山奈素荧光发射波长的变化以及荧光强度的增强表明了包合物的形成,用荧光双倒数法计算了环糊精及其衍...     

紫外光谱法研究环糊精/精(口恶)唑禾草灵超分子复合体

采用紫外光谱法研究了β-环糊精(β-CD)、羟丙基-β-环糊精(HP-β-CD)和部分甲基化β-环糊精(RAMEB)与精(口恶)唑禾草灵(FE-p)间的超分子作用.在体积比为1:4的乙醇-水溶剂中,在298.15～318.15K的温度范围内,3种环糊精均能与FE-p形成稳定的1:1型的超分子复合体,其结合常数值大小依次是KRAMEB>KHP-β-CD＞KβCD,且随着温度的升高而降低.经过计算,热力学参数△G,△H和△S均为负值,说明结合反应是放热反应且能自发进行,焓变是形成超分子复合体的主要驱动力,符合熵焓补偿效应.     

荧光光谱法研究β-环糊精衍生物对氟比洛芬的包结作用

采用荧光光谱法研究了β-CD衍生物对氟比洛芬的包结作用。实验考察了β-CD衍生物种类及其浓度、乙醇含量、离子强度及pH等因素对包结作用的影响。实验结果表明:随β-CD衍生物浓度的增大,荧光强度逐渐增强,其中HP-β-CD的增强效果最明显,即表明HP-β-CD对氟比洛芬的包结作用最强。1/(F-F0)对1/[CD]所作的双倒数曲线为直线,说明氟比洛芬与环糊精形成1∶1的包合物。随离子强度增大,包合作用增强;溶液中乙醇比例和pH越大,HP-β-CD与氟比洛芬包结物的包合作用越弱。     

氟哌酸-羟丙基环糊精固体包结物的制备及其性质研究

氟哌酸是一种广谱,安全,有效,可供口服的抗感染药.因其在水溶液中溶解度较低,影响肠胃对氟哌酸的吸收,降低了生物利用度.本文通过共沉淀法合成了固体羟丙基-β-环糊精(HP-β-CD)-氟哌酸包结配合物,并经一维,二维核磁共振技术和荧光,差示扫描量热等方法,证明包结物的包结比为1:1,得出包结物的形成常数,并提出包结物的空间构型.     

β-环糊精衍生物对α-苯丙酸包结作用的研究

用紫外光谱法研究了系列β-环糊精衍生物(羟丙基-β-环糊精、羟乙基-β-环糊精和甲基-β-环糊精)对α-苯丙酸的包结作用,考察了不同β-环糊精衍生物对不同存在状态的α-苯丙酸的包结行为。结果说明,α-苯丙酸与β-环糊精衍生物形成的包合物的包合比为1∶1,三种主体环糊精的包结能力强弱顺序为:羟乙基-β-环糊精羟丙基-β-环糊精甲基-β-环糊精。羟丙基-β-环糊精适合包结分子状态的α-苯丙酸,而不易包结离子状态的α-苯丙酸。     

羧基-β-环糊精衍生物及其二茂铁包络物的制备与性质研究

制备了一种羧基-β-环糊精衍生物,并将它包络二茂铁,制得了二茂铁-羧基-β-环糊精包络物,用红外光谱、紫外可见光谱、1HNMR、13CNMR等方法表征了羧基-β-环糊精及二茂铁包络物。由于羧基-β-环糊精衍生物破坏了β-环糊精的分子内氢键,并修饰了羧基,使得其水溶性得到明显的提高。研究了包络物的电化学性质,发现其具有良好的氧化还原可逆性和水溶性,可用作电子传递媒介体,循环伏安法测定表明,其检出限为10-7mol/L,表明这类氧化还原具有很高的灵敏度,可以用作性能优异的电化学探针和电流型生物传感器的电子媒介体。     

Fabrication of fucoxanthin/2-hydroxypropyl-β-cyclodextrin inclusion complex assisted by ultrasound procedure to enhance aqueous solubility,stability and antitumor effect of fucoxanthin

Fucoxanthin (Fx) possesses multiple bioactivities such as antitumor, antioxidant and anti-inflammatory activities, but its application is limited due to the poor water solubility, low bioavailability, and instability to some external harsh conditions. In this study, a stable inclusion complex of Fx and 2-hydroxypropyl-β-cyclodextrin (2-HP-β-CD) was prepared with the aid of ultrasound, which was characterized by scanning electron microscope, Fourier transform infrared spectroscopy, powder X-ray diffraction, and differential scanning calorimetry techniques. The phase solubility analysis and absorption spectroscopy results showed that Fx formed stoichiometry 1:2 inclusion complex with 2-HP-β-CD, and this could be well proved by molecular simulation. Structural analyses and molecular docking study indicated that Fx was successfully encapsulated into the cavity of 2-HP-β-CD, promoting it soluble in water and stable against heat, storage and gastrointestinal environments. In addition, Fx/2-HP-β-CD inclusion complex exhibited excellent antitumor activity against HCT116 and Caco-2 cell lines with IC₅₀ values of 12.0 μΜ and 14.86 μΜ, respectively. Therefore, it could be a potentially promising way to promote the application of Fx in pharmaceuticals and functional foods by HP-β-CD encapsulation strategy.     

Fluorescence enhancement of the aflatoxin B1 by forming inclusion complexes with some cyclodextrins and molecular modeling study

The interaction between the aflatoxin B₁ (AFB₁) and three cyclodextrins, α-cyclodextrin (α-CD), β-cyclodextrin (β-CD) and heptakis-2,6-dimethyl-o-β-cyclodextrin (ome-CD), was studied by spectrofluorescence technique. It was found that the inclusion association behavior occurs for the complexes of cyclodextrins with AFB₁. The fluorescence of AFB₁ is generally enhanced in the complexes with cyclodextrins in aqueous solutions. The inclusion complex constants of the three types of cyclodextrins at different temperatures were evaluated from Benesi-Hildebrand plot and also by non-linear regression analysis. These cyclodextrins can only form the 1:1 (host:guest) inclusion complex in the studied temperature range of 20-50 °C. The enthalpy (ΔH°) and entropy (ΔS°) changes of complexation were extracted from the temperature dependency of complex formation constants (K). Temperature-dependent measurements showed that the association step is controlled by enthalpy-entropy compensation effect. The use of ome-CD generally resulted in the greatest fluorescence intensity. On the other hand, the discrepancy between the exhibited enhanced fluorescence and thermodynamic parameters (ΔG°) is proposed to be different only by the orientation of the AFB₁ within the cyclodextrin cavity. To find the most favorable structure, the geometry of complex was investigated by molecular modeling approach employing the semiemperical HF-SCF calculations.     

Encompassment of Benzyl Isothiocyanate in cyclodextrin using ultrasonication methodology to enhance its stability for biological applications

The use of methodical and innovative sonication method has been explored for the fabrication of inclusion complex of Benzyl Isothiocyanate, a potential anticancer and -antimicrobial agent. The advancement involved investigation of inclusion behaviour, characterisation and an in-depth study of thermal and UV stability of Benzyl Isothiocyanate with cyclodextrins; β-CD and hp-β-CD. The sonication driven encompassment in cyclodextrins helped to overcome the hindrance of low solubility and high volatility. Investigations of physical and thermodynamic parameters using UV–visible spectroscopy, FTIR, XRD, TGA etc confirmed stability of inclusion complexes. Both β-CD and hp-β-CD based inclusion complexes retained the antimicrobial property of the free Benzyl Isothiocyanate, indicating their potential utility as antimicrobial agents. Haematological safety and cellular uptake data gives direction to in-depth analysis for its exploitation of anti-tumour activity.     

Synthesis and preparation of biocompatible and pH-responsive cyclodextrin-based nanoparticle

As a temporarily protective reaction for active hydrogen group, acetylation is reversible and responsive to low pH value. According to the reaction, pH-sensitive β-cyclodextrin (β-CD) was synthesized in the first step of our research. During the synthesis, the acetal groups including linear acetal (LA) groups and cyclic acetal (CA) groups were successfully modified onto β-CD. Particularly, the structural details of acetalated β-CD (Ac-β-CD) were greatly influenced by reaction time. Furthermore, in respect to water solubility, Ac-β-CDs exhibited different pH response properties due to their different structure. In the second step, Ac-β-CD1 nanoparticles were prepared by a single oil-in-water (O/W) emulsion technique using a biocompatible emulsifier, gelatin. Meanwhile, gelatin was absorbed onto the surface of nanoparticle, which was confirmed by FTIR spectra. The formed nanoparticles showed monodispersion and nearly spherical morphology. In order to obtain optimal preparing conditions, the effects of preparative parameters such as gelatin concentration, Ac-β-CD concentration, and water/oil ratio on properties including diameters and zeta potential as well as gelatin content were investigated. Moreover, the pH response properties of nanoparticle were characterized by transparency of nanoparticle solution. Finally, in vitro cell culture confirmed that Ac-β-CD nanoparticle could support cell survival and enhance cell viability.